Baghdad, Iraq (CNN) -- A verbal altercation between four U.S. soldiers in Iraq preceded the fatal shooting of two and wounding of a third, a U.S. military official said Wednesday.

Spc. Neftaly Platero is in pre-trial confinement, suspected in the deaths of Spc. John Carrillo Jr. and Pfc. Gebrah P. Noonan, the military said Tuesday.

Carrillo, 20, of Stockton, California, and Noonan, 26, of Watertown, Connecticut, died Friday of injuries sustained in a "non-combat" incident that occurred a day earlier, the U.S. Department of Defense said.

"The next of kin of the victims were notified that it appears a verbal altercation broke out involving four soldiers, after which the suspect allegedly took his weapon and began shooting the other soldiers," a military official said Wednesday. "The Army is conducting an investigation into the deaths."

Carrillo's mother, Desiree Carrillo, said Tuesday that her son was a good son and a good father to a 3-year-old and a 3-month-old.

"He was a very young father, and he was in school, but he joined the military to provide more for his family," she said.

Desiree Carrillo said the military notified them of Carrillo's death on Friday after family members learned through the media their son may have been killed by another soldier.

Several people posted rest-in-peace messages on what appears to be Noonan's Facebook page. The page of "Gebrah Noonan" also lists "Neftaly Platero" -- the same name as the suspect -- as a Facebook friend.